Symptoms of jumped Timing Chain?

What are the symptoms of a jumped timing chain and how can I check without tearing it apart?

Was driving my truck (22RE 5Spd). The idle began surging from about 1500 rpm and drop to about 600. (Was better with the foot on the break). It's been doing this intermitantly on and off for the last 6 months or so but always got better. Usually happens in the winter. Anyway it was surging for a couple of minutes and then the idle suddenly dropped to about 400 and stayed there. The truck feels like it lost about 30% of power but other than that runs smooth.

Last night I checked the plugs, wires, rotor, etc... and the look OK. Also systematically pulled the plugs one at a time from the injectors with the engine running to see if I had a dead cyl. Each time I pulled a plug the engine would start to miss and the RPM would drop. Looks like all cyls are firing.

Only other thing I can think of is a jumped timing chain.

So the questions are:
- What are the symptoms of a jumped chain and how can I check without pulling it apart?
- Can I somehow check with crank at TDC and rotor position, etc?
- Will a 22R still run with a jumped chain?
- Is there something related to the surging idle issue that might be doing this?

The engine still runs smooth but has about a 30% loss in power and no codes

Sounds like what mine was doing (1990 22re, 5spd) I found out it was my Maf, or afm. The electronic air flow sensor that's attached inline with your airbox, mounted on the driver side front of your truck. I got a used one from a salvage yard that worked great for a whopping 3 months, then I bought a new one from rock auto finally.

So I tore into the truck this weekend and it looks like the timing chain jumped 1 tooth. Was really surprised it ran as smooth as it did and didn't throw any codes. just had to pull the valve cover, remove the cam sprocket and move the chain 1 link over. was easier than I thought and took less than an hour. Got it back together and in time and it's running great